Field of the Invention
The invention relates to a method for determining at least the velocity of a flowing medium. Furthermore, the invention relates to a device for determining at least the velocity of a medium flowing through a pipe. The medium is, thereby, preferably at least partially gaseous, i.e., for example, a gas-dust-mixture.
Description of Related Art
In modern processing systems, it is often necessary to monitor or to quantitatively evaluate the flow or flowing of a medium through a pipe, i.e., for example, a pipeline or piping arrangement. For this, measuring devices are known for determining the volume or mass flow, which implement the vortex-, Coriolis-, ultrasound- or float-principle for the respective measurement.
A device for determining the velocity of a flowing medium is disclosed, for example, in the German Patent DE 35 04 622 C2 and corresponding U.S. Pat. No. 4,708,021. Two sensors are thereby arranged shifted to one another along a pipe conveying the medium. The sensors or the measuring principles implemented with them lead to the signals obtained by the sensors being independent of inhomogeneities of the flowing medium. The velocity of the inhomogeneities, and thus, the medium is deter- mined using a cross-correlation of the signals. Details for the practical implementation, however, are not described. Furthermore, the construction with two sensors arranged shifted to one another is complicated and also requires a correspondingly large amount of space around the measuring arrangement.
European Patent Application EP 2 559 973 A1 and corresponding U.S. Pat. No. 9,243,939 B2 describe a construction for determining the velocity of a medium in a pipe by means of laser beams that vertically cross the pipe. Vortices are thereby generated in the medium, in order to determine the velocity from the noise in the received laser signals.
In a similar construction according to U.S. Patent Application Publication 2013/0041599 A1, vortices are also generated and microwave signals are used.